Floodlight with emergency quencher for incandescent lamp filament



Ju y 1955 E. M. BECKER ET AL 2,713,630

F LIGHT WITH EMERGENCY QUENCHER INCANDESCENT LAMP FILAMENT Filed March31, 1950 2 Sheets-Sheet l July 1955 E M. BECKER ET AL- 2,713,630

FLOODLIGi-IT WITH EMERGENCY QUENCHER FOR INCANDESCENT LAMP FILAMENTFiled March 31. 1950 2 Sheets-Sheet 2 I x J T I 3:33 x a? 12 2? 5 J5 INV EN TORS bad FLQODLTGHT WITH EMERQEN CY QUENHER FUR El IQANDESQEr TlLAltiP FHLAR-QENT Earl M. Becker, Fittshnrgh, and .lohn .17. Bridge,Turtle Creek, Pa., assignors to Mine Safety Appliances Company,Pittsburgh, Pa., a corporation of Pennsylvania Application March 31,195i), Serial No. 153,218 3 Claims. (Cl. 24t'l11.3)

This invention relates to the removal of heat from the filament of abroken incandescent lamp so that the filament will not ignitesurroundnig explosive gas.

Occasionally, incandescent fioodlights and the like which are used inexplosive atmospheres, such as found in coal mines, are brokenaccidentally. The filament of a piece or splinter of the bulb remainingattached to the stem of the lamp prevents the quencher from engaging thehot filament eifectively.

It is an object of this invention to provide in such a light a device ofsimple construction which insures that Most suitably, bulb. The side ofthe tially spaced points in by a bulb crusher that loop. The quencherand crusher are constantly urged toward the socket by spring means.Consequently, if the bulb is broken accidentally, the crusher will beredriving the lamp ahead the in stantthe bulb is broken, so that thecircuit to the lamp will be broken and the time that it takes thequencher and filament to come together will be shortened.

The preferred embodiment of the invention is illus Fig. 3 is afragmentary section, similar to Fig. 2, showing the quencher pressedagainst the filament of a broken lamp.

Referring to Figs. 1 and 2 of the drawings, a floodlight or spotlightcase 1, adjustably mounted on the cover 2 of a battery box (not shown),contains a reflector 3 and has a lens 4 closing its front end. The lensand a sealing gasket 5 between it and the reflector are held in place bya retaining ring 6. The center of the reflector is provided with anopening, from which a rigid sleeve 7 projects backward into the case.Slidably mounted in this sleeve is the tubular liner 8 of an electriclamp socket 9 which is provided around the liner With an annular recess1 that receives the sleeve. inside the back part of the socket liner isa pair of electric contacts 12, from which wires 13 tery box cover. Therear end of the socket has a rearwardly projecting bracket 14, in whicha focusing screw 15, rotatably mounted in the back of the case, isthreaded for adjusting the socket lengthwise of sleeve 7.

Rigidly mounted on top of the lamp socket is a tube 17 that extendsloosely through an opening 18 in the reflector. The passage through thistube has an interior shoulder 19 which spaces a rod 20, that extendsslidably through the tube, from the side wall of the passage. The rodprojects from both ends of the tube. The rear end of the rod is roundand carries a nut 22. The nut is urged away from an integral collar 23,which encircles the tube, by means of a coil spring 24 compressedbetween Most of the rod is rectangular in cross section so that it cannot turn in shoulder 1'9, but for a short distance in front of nut 22the rod has a cylindrical portion 25 for a purpose that will appearpresently. The front The wire extends down below the rod in a verticalloop 26, which is substantially coaxial with the lamp socket behind it.This loop encircles and portion of the glass bulb 27 of an incandescentlamp, whose stem 23 is slidably mounted in socket liner 3. As the loopengages the bulb at a plurality of circumferentially spaced points infront of its greatest diameter or circumference, the coil spring 24,through the medium of the loop, presses the lamp back in the socket sothat the usual electric contacts on the lamp will firmly engage socket The Wire extends upward and forward from the rod and then down in frontof the lamp. The wire is coiled around and supports a of suflicient massto quickly remove brought into intimate engagement With each other.button is coaxial with the lamp socket, and preferably is spaced a shortdistance from the front of the lamp bulb. This spacing is maintained byengagement of the loop with the lamp bulb.

If the lens of the fioodlight is broken and the object that broke it, ora fragment of the lens, also breaks the lamp bulb.

its forward position. loop, however, appears in case some of the glassof the bulb remains projecting forward from the lamp stem and inengagement with the loop. Any such fragment e able to prevent loop 26from moving rearward, because the rearward pressure of the loop willpress the glass, which necessarily bows out behind the loop, inwardtoward the axis of the loop and thereby will break the glass. In otherwords, the loop will squeeze towards its center any fragments of glassremaining in engagement with it after the lamp has been broken. Theresult is that the loop serves to crush any portion of the broken lampbulb that, otherwise, might prevent the loop from moving toward thesocket. For best results, it is preferred that the crusher loop besubstantially triangular in form so that it will engage the bulb at onlythree circumferentially and substantially equally spaced points. If itengages the bulb at more than three points, the pressure it exertsagainst the bulb at each point is reduced. Due to the fact that thequencher button initially is spaced from the bulb, it has an opportunityto acquire velocity before it reaches the point where any piece of glasscould be.

[\t the moment the bulb is broken and the crusher loop is moved towardthe socket by means of spring 24,

the quencher 33 is moved rearward simultaneously and 1 strikes andcrushes the hot filament 34-, as shown in Fig. 3. The rod 20 movesbackward in tube 17 until nut 22 strikes the back of the case 1. Thesmashing of the filament against the much cooler quencher button assuresa considerable area of contact between them, so

that heat is removed from the filament instantly b-- fore explosive gasoutside of the fioodlight can enter the lamp through the broken lens andreach the filament.

To further shorten the interval between the moment the glass bulb isbroken and the instant the quencher strikes the filament, and also toprevent contact of the quencher with the filament from blowing the lampfuse, the lamp stem is moved forward in the socket the instant the bulbis broken. This is accomplished by a coil spring 36 inside the socketliner. weaker than spring 24, normally is compressed between the innerend of the lamp and the back part of the socket. However, as soon as thelamp bulb is broken, spring 36 drives the lamp stem ahead at the sametime that the quencher is driven back by the other spring. The momentthe lamp is moved ahead in the socket, the electrical connection betweenthe lamp and socket contacts 12 is broken, as shown in Fig. 3, so thatthere will be no short circuit that will blow the fuse. Engagement ofnut 22 with the back of the case prevents spring 24 from driving thelamp stem back into the socket.

The broken bulb can be removed and replaced by a good one by pulling rod20 forward far enough to position cylindrical portion 25 of the rodinside shoulder 19. The rod then can be rotated 180 and released. 7

The rectangular portion of the rod will be drawn back past shoulder 19so that the rod can not turn back to its original position. While loop26 and quencher 33 are pointed upward, the lamps can be changed.

It has been found that a floodlight or the like constructed inaccordance with this invention always operates as intended when the bulbis broken. Sufficient heat is removed from the filament by means of thequencher This spring, which is to prevent the filament from ignitingexplosive atmosphere around the lamp. The quencher performs its functionalmost instantly, before any of the exposive atmosphere can reach thehot filament.

According to the provisions of the patent statutes, we have explainedthe principle of our invention and have illustrated and described whatwe now consider to represent its best embodiment. However, we desire tohave it understood that, within the scope of the appended claims, theinvention may be practiced otherwise than as specifically illustratedand described.

We claim:

1. A fioodlight comprising an electric socket, an incandescent lampmounted therein and provided with a filament enclosed in a glass bulb, afilament quencher disposed in front of the bulb, a bulb crusher engagingthe side of the bulb at only three circumferentially spaced points infront of its maximum diameter, and spring means urging the quencher andcrusher rearward to ward the socket, whereby if the bulb is brokenaccidentally the crusher will be moved rearward and the quencher will bedriven against the lamp filament to quench it.

2. A floodlight comprising an electric socket, an incandescent lampmounted therein and provided with a filament enclosed in a glass bulb, afilament quencher disposed in front of the bulb and spaced therefrom, arigid loop surrounding the bulb and engaging the side of the bulb atonly three circumferentially spaced points in front of its maximumdiameter, a rod disposed beside the lamp and slidable lengthwise of thesocket, the rod being rigidly connected to the quencher and loop, and a.spring urging the rod rearward, whereby if the bulb is brokenaccidentally the loop will be released and the rod will pull thequencher against the lamp filament to quench it.

3. A fioodlight comprising an electric socket, an in-- candescent lampremovably mounted therein and provided with a filament enclosed in aglass bulb, a filament quencher disposed in front of the bulb and spacedtherefrom, a bulb crusher rigidly connected to the quencher and engagingthe side of the bulb at only three circumferentially spaced points infront of its maximum diameter, and spring means for effecting relativemovement of the quencher and lamp filament toward each other if the bulbis broken accidentally.

References fitted in the filc of this patent UNITED STATES PATENTSLindbloom et al. June 24, 1941 Ceader May 28, 1946 Mines.

